Direct Photoluminescence Probing of Ferromagnetism in Monolayer Two-Dimensional CrBr<sub>3</sub>.

Zhang, Zhaowei; Shang, Jingzhi; Jiang, Chongyun; Rasmita, Abdullah; Gao, Weibo; Yu, Ting · Nano Lett · 2019

basic_science · Level V

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Abstract

Atomically thin magnets are the key element to build up spintronics based on two-dimensional materials. The surface nature of two-dimensional ferromagnet opens up opportunities to improve the device performance efficiently. Here, we report the intrinsic ferromagnetism in atomically thin monolayer CrBr<sub>3</sub>, directly probed by polarization resolved magneto-photoluminescence. The spontaneous magnetization persists in monolayer CrBr<sub>3</sub> with a Curie temperature of 34 K. The development of magnons by the thermal excitation is in line with the spin-wave theory. We attribute the layer-number-dependent hysteresis loops in thick layers to the magnetic domain structures. As a stable monolayer material in air, CrBr<sub>3</sub> provides a convenient platform for fundamental physics and pushes the potential applications of the two-dimensional ferromagnetism.